Rotary motion passive end effector for surgical robots in orthopedic surgeries

ABSTRACT

A passive end effector of a surgical system includes a base connected to a rotational disk, and a saw attachment connected to the rotational disk. The base is attached to an end effector coupler of a robot arm positioned by a surgical robot, and includes a base arm extending away from the end effector coupler. The rotational disk is rotatably connected to the base arm and rotates about a first location on the rotational disk relative to the base arm. The saw attachment is rotatably connected to the rotational disk and rotates about a second location on the rotational disk. The first location on the rotational disk is spaced apart from the second location on the rotational disk. The saw attachment is configured to connect to a surgical saw including a saw blade configured to oscillate for cutting. The saw attachment rotates about the rotational disk and the rotational disk rotates about the base arm to constrain cutting of the saw blade to a range of movement along arcuate paths within a cutting plane.

FIELD

The present disclosure relates to medical devices and systems, and moreparticularly, robotic systems and related end effectors for controllingcutting of anatomical structures of a patient, and related methods anddevices.

BACKGROUND

There are a number of surgical interventions requiring osteotomy, i.e.cutting an anatomical structure such as a bone along a target plane.Total knee arthroplasty typically requires cutting both the femoralepiphysis and tibial epiphysis in order to remove the damaged bone andcartilage and install a knee prosthesis. A surgeon may perform five ormore cuts on the femur and one or more cuts on the tibia using anoscillating surgical saw.

During orthopedic surgeries, including joints and knees, it is importantto accurately align and stabilize the saw while cutting a desiredlocation on a bone. The surgeon's limited visibility to the surgicalsite combined with the difficultly in controlling movement of the sawcreates a risk that an undesired part of a bone or adjacent tissuebecomes cut. Vibrations generated by the saw while cutting can reducethe accuracy of the cuts. During knee surgery, the precision of a bonecut (planar cuts) affects how precisely the implant can be connected tothe exposed bone.

During some knee surgeries, a jig is screwed to a bone for guiding asurgeon's movement of a saw while cutting. Error in jig placement andlimited stability of the saw blade during cutting can limit precision ofthe cuts. Moreover, contact between the saw blade and the jig cangenerate debris which risks entering the patient.

SUMMARY

Some embodiments of the present disclosure are directed to a passive endeffector of a surgical system that includes a base connected to arotational disk and further includes a saw attachment connected to therotational disk. The base is attached to an end effector coupler of arobot arm positioned by a surgical robot, and includes a base armextending away from the end effector coupler. The rotational disk isrotatably connected to the base arm and rotates about a first locationon the rotational disk relative to the base arm. The saw attachment isrotatably connected to the rotational disk and rotates about a secondlocation on the rotational disk. The first location on the rotationaldisk is spaced apart from the second location on the rotational disk.The saw attachment is configured to connect to a surgical saw includinga saw blade configured to oscillate for cutting. The saw attachmentrotates about the rotational disk and the rotational disk rotates aboutthe base arm to constrain cutting of the saw blade to a range ofmovement along arcuate paths within a cutting plane.

Some other embodiments of the present disclosure are directed to asurgical system that includes a tracking system, a surgical robot, and apassive end effector. The tracking system is configured to determine apose of an anatomical structure to be cut by a saw blade and todetermine a range of movement of the saw blade along arcuate pathswithin a cutting plane. The surgical robot includes a robot base, arobot arm rotatably connected to the robot base, at least one motoroperatively connected to move the robot arm relative to the robot base,and at least one controller connected to the at least one motor. Thepassive end effector includes a base, a rotational disk, and a sawattachment. The base is configured to attach to an end effector couplerof the robot arm and includes a base arm extending away from the endeffector coupler. The rotational disk is rotatably connected to the basearm and rotates about a first location on the rotational disk relativeto the base arm. The saw attachment is rotatably connected to therotational disk and rotates about a second location on the rotationaldisk. The first location on the rotational disk is spaced apart from thesecond location on the rotational disk. The saw attachment is configuredto connect to a surgical saw including a saw blade configured tooscillate for cutting. The saw attachment rotates about the rotationaldisk and the rotational disk rotates about the base arm to constraincutting of the saw blade to a range of movement along arcuate pathswithin a cutting plane.

The at least one controller is configured to determine a pose of atarget plane based on a surgical plan defining where the anatomicalstructure is to be cut and based on the pose of the anatomicalstructure. The at least one controller is further configured to generatesteering information based on comparison of the pose of the target planeand the determined range of movement of the saw blade along arcuatepaths within the cutting plane. The steering information indicates wherethe passive end effector needs to be moved to position the cutting planeof the saw blade to be aligned with the target plane and so the sawblade is within the range of movement from the anatomical structure tobe cut.

Other surgical systems, passive end effectors, and corresponding methodsand computer program products according to embodiments will be or becomeapparent to one with skill in the art upon review of the followingdrawings and detailed description. It is intended that all such surgicalsystems, passive end effectors, and corresponding methods and computerprogram products be included within this description, be within thescope of the present disclosure, and be protected by the accompanyingclaims. Moreover, it is intended that all embodiments disclosed hereincan be implemented separately or combined in any way and/or combination.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the disclosure and are incorporated in a constitute apart of this application, illustrate certain non-limiting embodiments ofinventive concepts. In the drawings:

FIG. 1 illustrates an embodiment of a surgical system according to someembodiments of the present disclosure;

FIG. 2 illustrates a surgical robot component of the surgical system ofFIG. 1 according to some embodiments of the present disclosure;

FIG. 3 illustrates a camera tracking system component of the surgicalsystem of FIG. 1 according to some embodiments of the presentdisclosure;

FIG. 4 illustrates an embodiment of a passive end effector that isconnectable to a robot arm and configured according to some embodimentsof the present disclosure;

FIG. 5 illustrates a medical operation in which a surgical robot and acamera system are disposed around a patient;

FIG. 6 illustrates an embodiment of an end effector coupler of a robotarm configured for connection to a passive end effector according tosome embodiments of the present disclosure;

FIG. 7 illustrates an embodiment of a cut away of the end effectorcoupler of FIG. 6;

FIG. 8 illustrates a block diagram of components of a surgical systemaccording to some embodiments of the present disclosure;

FIG. 9 illustrates a block diagram of a surgical system computerplatform that includes a surgical planning computer which may beseparate from and operationally connected to a surgical robot or atleast partially incorporated therein according to some embodiments ofthe present disclosure;

FIG. 10 illustrates an embodiment of a C-Arm imaging device that can beused in combination with the surgical robot and passive end effector inaccordance with some embodiments of the present disclosure;

FIG. 11 illustrates an embodiment of an O-Arm imaging device that can beused in combination with the surgical robot and passive end effector inaccordance with some embodiments of the present disclosure; and

FIG. 12 illustrates an exploded view of components of a passive endeffector that can be connected to a surgical saw and which areconfigured in accordance with some embodiments of the presentdisclosure;

FIG. 13 illustrates the assembled passive end effector of FIG. 12connected to a surgical saw and configured in accordance with someembodiments of the present disclosure;

FIGS. 14a-14d illustrate a sequence of top views of the passive endeffector and surgical saw of FIG. 13 in which the surgical saw isrotated about the rotational disk and the rotational disk is rotatedabout the base arm to provide a range of movement of the saw blade alongarcuate paths within a cutting plane in accordance with some embodimentsof the present disclosure;

FIG. 15 illustrates a combination of the top views of the passive endeffector and surgical saw of FIGS. 14a and 14c to show a range of themovement of the saw blade along a horizontal axis that is provided byrotation of the surgical saw about the rotational disk and rotation ofthe rotational disk about the base arm;

FIG. 16 illustrates a light source, a tracking ring, and a light pulsedetector configured in accordance with one embodiment to provide inputto a tracking system for determining an arcuate path through which thesaw blade moves; and

FIG. 17 illustrates a light source, a tracking ring, and a light pulsedetector configured in accordance with another embodiment to provideinput to a tracking system for determining an arcuate path through whichthe saw blade moves.

DETAILED DESCRIPTION

Inventive concepts will now be described more fully hereinafter withreference to the accompanying drawings, in which examples of embodimentsof inventive concepts are shown. Inventive concepts may, however, beembodied in many different forms and should not be construed as limitedto the embodiments set forth herein. Rather, these embodiments areprovided so that this disclosure will be thorough and complete, and willfully convey the scope of various present inventive concepts to thoseskilled in the art. It should also be noted that these embodiments arenot mutually exclusive. Components from one embodiment may be tacitlyassumed to be present or used in another embodiment.

Various embodiments disclosed herein are directed to improvements inoperation of a surgical system when performing surgical interventionsrequiring osteotomy. A passive end effector is disclosed that isconnectable to a robot arm positioned by a surgical robot. The passiveend effector includes a base, a rotational disk, and a saw attachment.The base is configured to attach to an end effector coupler of the robotarm, and includes a base arm extending away from the end effectorcoupler. The rotational disk is rotatably connected to the base arm androtates about a first location on the rotational disk relative to thebase arm. The saw attachment is rotatably connected to the rotationaldisk and rotates about a second location on the rotational disk. Thefirst location on the rotational disk is spaced apart from the secondlocation on the rotational disk. The saw attachment is configured toconnect to a surgical saw having a saw blade which is configured tooscillate for cutting. The saw attachment rotates about the rotationaldisk and the rotational disk rotates about the base arm to constraincutting of the saw blade to a range of movement along arcuate pathswithin a cutting plane.

As will be further explained below, the surgical robot can determine apose of a target plane based on a surgical plan defining where ananatomical structure is to be cut and based on a pose of the anatomicalstructure. The surgical robot can also generate steering informationbased on comparison of the pose of the target plane and a determinedrange of movement of the saw blade along arcuate paths within thecutting plane. The steering information indicates where the passive endeffector needs to be moved to position the cutting plane of the sawblade to be aligned with the target plane and so the saw blade is withinthe range of movement from the anatomical structure to be cut. Thesteering information can be used to automatically position the passiveend effector relative to the anatomical structure and/or to provideguidance to an operator who positions the passive end effector relativeto the anatomical structure.

These and other related embodiments can operate to improve the precisionof the guidance of the saw blade compared to other robotic and manual(e.g., jigs) solutions for surgeries. The planar mechanisms of thepassive end effector can allow the surgeon to concentrate oninterpreting the direct force feedback while cutting bones using asurgical saw that is guided by the passive end effector, while theplanar mechanisms constrain the cutting plane to be aligned with thetarget plane. The surgeon may also more accurately monitor and controlthe speed of bone removal based on audio and/or visual notificationfeedback provided through the surgical robot.

These embodiments can provide guidance during joint surgeries andespecially knee surgery with high precision, high rigidity, sufficientworkspace and direct force feedback. As will be explained in detailbelow, a tracking system can be used to precisely align the cuttingplane with the target plane for cutting a bone. High precision cuts maybe achieved by the planar mechanisms constraining the cutting plane toremaining aligned with the target plane while a surgeon moves the sawblade along the cutting plane and directly senses force feedback of thesaw blade cutting bone. Moreover, these embodiments can be rapidlydeployed into surgical practices through defined changes in existingaccepted surgery workflows.

FIG. 1 illustrates an embodiment of a surgical system 2 according tosome embodiments of the present disclosure. Prior to performance of anorthopedic surgical procedure, a three-dimensional (“3D”) image scan maybe taken of a planned surgical area of a patient using, e.g., the C-Armimaging device 104 of FIG. 10 or O-Arm imaging device 106 of FIG. 11, orfrom another medical imaging device such as a computed tomography (CT)image or MRI. This scan can be taken pre-operatively (e.g. few weeksbefore procedure, most common) or intra-operatively. However, any known3D or 2D image scan may be used in accordance with various embodimentsof the surgical system 2. The image scan is sent to a computer platformin communication with the surgical system 2, such as the surgical systemcomputer platform 900 of FIG. 9 which includes the surgical robot 800(e.g., robot 2 in FIG. 1) and a surgical planning computer 910. Asurgeon reviewing the image scan(s) on a display device of the surgicalplanning computer 910 (FIG. 9) generates a surgical plan defining atarget plane where an anatomical structure of the patient is to be cut.This plane is a function of patient anatomy constraints, selectedimplant and its size. In some embodiments, the surgical plan definingthe target plane is planned on the 3D image scan displayed on a displaydevice.

The surgical system 2 of FIG. 1 can assist surgeons during medicalprocedures by, for example, holding tools, aligning tools, using tools,guiding tools, and/or positioning tools for use. In some embodiments,surgical system 2 includes a surgical robot 4 and a camera trackingsystem 6. Both systems may be mechanically coupled together by anyvarious mechanisms. Suitable mechanisms can include, but are not limitedto, mechanical latches, ties, clamps, or buttresses, or magnetic ormagnetized surfaces. The ability to mechanically couple surgical robot 4and camera tracking system 6 can allow for surgical system 2 to maneuverand move as a single unit, and allow surgical system 2 to have a smallfootprint in an area, allow easier movement through narrow passages andaround turns, and allow storage within a smaller area.

An orthopedic surgical procedure may begin with the surgical system 2moving from medical storage to a medical procedure room. The surgicalsystem 2 may be maneuvered through doorways, halls, and elevators toreach a medical procedure room. Within the room, the surgical system 2may be physically separated into two separate and distinct systems, thesurgical robot 4 and the camera tracking system 6. Surgical robot 4 maybe positioned adjacent the patient at any suitable location to properlyassist medical personnel. Camera tracking system 6 may be positioned atthe base of the patient, at the patient shoulders, or any other locationsuitable to track the present pose and movement of the pose of tracksportions of the surgical robot 4 and the patient. Surgical robot 4 andcamera tracking system 6 may be powered by an onboard power sourceand/or plugged into an external wall outlet.

Surgical robot 4 may be used to assist a surgeon by holding and/or usingtools during a medical procedure. To properly utilize and hold tools,surgical robot 4 may rely on a plurality of motors, computers, and/oractuators to function properly. Illustrated in FIG. 1, robot body 8 mayact as the structure in which the plurality of motors, computers, and/oractuators may be secured within surgical robot 4. Robot body 8 may alsoprovide support for robot telescoping support arm 16. In someembodiments, robot body 8 may be made of any suitable material. Suitablematerial may be, but is not limited to, metal such as titanium,aluminum, or stainless steel, carbon fiber, fiberglass, or heavy-dutyplastic. The size of robot body 8 may provide a solid platformsupporting attached components, and may house, conceal, and protect theplurality of motors, computers, and/or actuators that may operateattached components.

Robot base 10 may act as a lower support for surgical robot 4. In someembodiments, robot base 10 may support robot body 8 and may attach robotbody 8 to a plurality of powered wheels 12. This attachment to wheelsmay allow robot body 8 to move in space efficiently. Robot base 10 mayrun the length and width of robot body 8. Robot base 10 may be about twoinches to about 10 inches tall. Robot base 10 may be made of anysuitable material. Suitable material may be, but is not limited to,metal such as titanium, aluminum, or stainless steel, carbon fiber,fiberglass, or heavy-duty plastic or resin. Robot base 10 may cover,protect, and support powered wheels 12.

In some embodiments, as illustrated in FIG. 1, at least one poweredwheel 12 may be attached to robot base 10. Powered wheels 12 may attachto robot base 10 at any location. Each individual powered wheel 12 mayrotate about a vertical axis in any direction. A motor may be disposedabove, within, or adjacent to powered wheel 12. This motor may allow forsurgical system 2 to maneuver into any location and stabilize and/orlevel surgical system 2. A rod, located within or adjacent to poweredwheel 12, may be pressed into a surface by the motor. The rod, notpictured, may be made of any suitable metal to lift surgical system 2.Suitable metal may be, but is not limited to, stainless steel, aluminum,or titanium. Additionally, the rod may comprise at thecontact-surface-side end a buffer, not pictured, which may prevent therod from slipping and/or create a suitable contact surface. The materialmay be any suitable material to act as a buffer. Suitable material maybe, but is not limited to, a plastic, neoprene, rubber, or texturedmetal. The rod may lift powered wheel 10, which may lift surgical system2, to any height required to level or otherwise fix the orientation ofthe surgical system 2 in relation to a patient. The weight of surgicalsystem 2, supported through small contact areas by the rod on eachwheel, prevents surgical system 2 from moving during a medicalprocedure. This rigid positioning may prevent objects and/or people frommoving surgical system 2 by accident.

Moving surgical system 2 may be facilitated using robot railing 14.Robot railing 14 provides a person with the ability to move surgicalsystem 2 without grasping robot body 8. As illustrated in FIG. 1, robotrailing 14 may run the length of robot body 8, shorter than robot body8, and/or may run longer the length of robot body 8. Robot railing 14may be made of any suitable material. Suitable material may be, but isnot limited to, metal such as titanium, aluminum, or stainless steel,carbon fiber, fiberglass, or heavy-duty plastic. Robot railing 14 mayfurther provide protection to robot body 8, preventing objects and orpersonnel from touching, hitting, or bumping into robot body 8.

Robot body 8 may provide support for a Selective Compliance ArticulatedRobot Arm, hereafter referred to as a “SCARA.” A SCARA 24 may bebeneficial to use within the surgical system 2 due to the repeatabilityand compactness of the robotic arm. The compactness of a SCARA mayprovide additional space within a medical procedure, which may allowmedical professionals to perform medical procedures free of excessclutter and confining areas. SCARA 24 may comprise robot telescopingsupport 16, robot support arm 18, and/or robot arm 20. Robot telescopingsupport 16 may be disposed along robot body 8. As illustrated in FIG. 1,robot telescoping support 16 may provide support for the SCARA 24 anddisplay 34. In some embodiments, robot telescoping support 16 may extendand contract in a vertical direction. Robot telescoping support 16 maybe made of any suitable material. Suitable material may be, but is notlimited to, metal such as titanium or stainless steel, carbon fiber,fiberglass, or heavy-duty plastic. The body of robot telescoping support16 may be any width and/or height in which to support the stress andweight placed upon it.

In some embodiments, medical personnel may move SCARA 24 through acommand submitted by the medical personnel. The command may originatefrom input received on display 34 and/or a tablet. The command may comefrom the depression of a switch and/or the depression of a plurality ofswitches. Best illustrated in FIGS. 4 and 5, an activation assembly 60may include a switch and/or a plurality of switches. The activationassembly 60 may be operable to transmit a move command to the SCARA 24allowing an operator to manually manipulate the SCARA 24. When theswitch, or plurality of switches, is depressed the medical personnel mayhave the ability to move SCARA 24 easily. Additionally, when the SCARA24 is not receiving a command to move, the SCARA 24 may lock in place toprevent accidental movement by personnel and/or other objects. Bylocking in place, the SCARA 24 provides a solid platform upon which apassive end effector 1100 and connected surgical saw 1140, shown inFIGS. 4 and 4, are ready for use in a medical operation.

Robot support arm 18 may be disposed on robot telescoping support 16 byvarious mechanisms. In some embodiments, best seen in FIGS. 1 and 2,robot support arm 18 rotates in any direction in regard to robottelescoping support 16. Robot support arm 18 may rotate three hundredand sixty degrees around robot telescoping support 16. Robot arm 20 mayconnect to robot support arm 18 at any suitable location. Robot arm 20may attach to robot support arm 16 by various mechanisms. Suitablemechanisms may be, but is not limited to, nuts and bolts, ball andsocket fitting, press fitting, weld, adhesion, screws, rivets, clamps,latches, and/or any combination thereof. Robot arm 20 may rotate in anydirection in regards to robot support arm 18, in embodiments, robot arm20 may rotate three hundred and sixty degrees in regards to robotsupport arm 18. This free rotation may allow an operator to positionrobot arm 20 as planned.

The passive end effector 1100 in FIGS. 4 and 5 may attach to robot arm20 in any suitable location. As will be explained in further detailbelow, the passive end effector 1100 includes a base, a first planarmechanism, and a second planar mechanism. The base is configured toattach to an end effector coupler 22 of the robot arm 20 positioned bythe surgical robot 4. Various mechanisms by which the base can attach tothe end effector coupler 22 can include, but are not limited to, latch,clamp, nuts and bolts, ball and socket fitting, press fitting, weld,adhesion, screws, rivets, and/or any combination thereof. The firstplanar mechanism extends between a rotatable connection to the base anda rotatable connection to a tool attachment mechanism. The second planarmechanism extends between a rotatable connection to the base and arotatable connection to the tool attachment mechanism. The first andsecond planar mechanisms pivot about the rotatable connections toconstrain movement of the tool attachment mechanism to a range ofmovement within a working plane. The tool attachment mechanism isconfigured to connect to a surgical saw 1140 having a saw blade. Thesurgical saw 1140 may be configured as a sagittal saw which oscillatesthe saw blade for cutting. The first and second planar mechanismsconstrain a cutting plane of the saw blade to be parallel to the workingplane.

The tool attachment mechanism may connect to the surgical saw 1140through various mechanisms that can include, but are not limited to, achannel, a screw, nut and bolt, clamp, latch, tie, press fit, or magnet.In some embodiments, a dynamic reference array 52 is attached to thepassive end effector 1100, e.g., to the tool attachment mechanism,and/or is attached to the surgical saw 1140. Dynamic reference arrays,also referred to as “DRAB” herein, are rigid bodies which may bedisposed on a patient, the surgical robot, the passive end effector,and/or the surgical saw in a navigated surgical procedure. The cameratracking system 6 or other 3D localization system is configured to trackin real-time the pose (e.g., positions and rotational orientations) oftracking markers of the DRA. The tracking markers include fiducials,such as the illustrated arrangement of balls. This tracking of 3Dcoordinates of tracking markers can allow the surgical system 2 todetermine the pose of the DRA 52 in any space in relation to the targetanatomical structure of the patient 50 in FIG. 5.

As illustrated in FIG. 1, a light indicator 28 may be positioned on topof the SCARA 24. Light indicator 28 may illuminate as any type of lightto indicate “conditions” in which surgical system 2 is currentlyoperating. For example, the illumination of green may indicate that allsystems are normal. Illuminating red may indicate that surgical system 2is not operating normally. A pulsating light may mean surgical system 2is performing a function. Combinations of light and pulsation may createa nearly limitless amount of combinations in which to communicate thecurrent operating conditions, states, or other operational indications.In some embodiments, the light may be produced by LED bulbs, which mayform a ring around light indicator 28. Light indicator 28 may comprise afully permeable material that may let light shine through the entiretyof light indicator 28.

Light indicator 28 may be attached to lower display support 30. Lowerdisplay support 30, as illustrated in FIG. 2 may allow an operator tomaneuver display 34 to any suitable location. Lower display support 30may attach to light indicator 28 by any suitable mechanism. Inembodiments, lower display support 30 may rotate about light indicator28. In embodiments, lower display support 30 may attach rigidly to lightindicator 28. Light indicator 28 may then rotate three hundred and sixtydegrees about robot support arm 18. Lower display support 30 may be ofany suitable length, a suitable length may be about eight inches toabout thirty four inches. Lower display support 30 may act as a base forupper display support 32.

Upper display support 32 may attach to lower display support 30 by anysuitable mechanism. Upper display support 32 may be of any suitablelength, a suitable length may be about eight inches to about thirty fourinches. In embodiments, as illustrated in FIG. 1, upper display support32 may allow display 34 to rotate three hundred and sixty degrees inrelation to upper display support 32. Likewise, upper display support 32may rotate three hundred and sixty degrees in relation to lower displaysupport 30.

Display 34 may be any device which may be supported by upper displaysupport 32. In embodiments, as illustrated in FIG. 2, display 34 mayproduce color and/or black and white images. The width of display 34 maybe about eight inches to about thirty inches wide. The height of display34 may be about six inches to about twenty two inches tall. The depth ofdisplay 34 may be about one-half inch to about four inches.

In embodiments, a tablet may be used in conjunction with display 34and/or without display 34. In embodiments, the table may be disposed onupper display support 32, in place of display 34, and may be removablefrom upper display support 32 during a medical operation. In additionthe tablet may communicate with display 34. The tablet may be able toconnect to surgical robot 4 by any suitable wireless and/or wiredconnection. In some embodiments, the tablet may be able to programand/or control surgical system 2 during a medical operation. Whencontrolling surgical system 2 with the tablet, all input and outputcommands may be duplicated on display 34. The use of a tablet may allowan operator to manipulate surgical robot 4 without having to move aroundpatient 50 and/or to surgical robot 4.

As illustrated in FIGS. 3 and 5, camera tracking system 6 works inconjunction with surgical robot 4 through wired or wirelesscommunication networks. Referring to FIGS. 1, 3 and 5, camera trackingsystem 6 can include some similar components to the surgical robot 4.For example, camera body 36 may provide the functionality found in robotbody 8. Robot body 8 may provide the structure upon which camera 46 ismounted. The structure within robot body 8 may also provide support forthe electronics, communication devices, and power supplies used tooperate camera tracking system 6. Camera body 36 may be made of the samematerial as robot body 8. Camera tracking system 6 may communicatedirectly to the tablet and/or display 34 by a wireless and/or wirednetwork to enable the tablet and/or display 34 to control the functionsof camera tracking system 6.

Camera body 36 is supported by camera base 38. Camera base 38 mayfunction as robot base 10. In the embodiment of FIG. 1, camera base 38may be wider than robot base 10. The width of camera base 38 may allowfor camera tracking system 6 to connect with surgical robot 4. Asillustrated in FIG. 1, the width of camera base 38 may be large enoughto fit outside robot base 10. When camera tracking system 6 and surgicalrobot 4 are connected, the additional width of camera base 38 may allowsurgical system 2 additional maneuverability and support for surgicalsystem 2.

As with robot base 10, a plurality of powered wheels 12 may attach tocamera base 38. Powered wheel 12 may allow camera tracking system 6 tostabilize and level or set fixed orientation in regards to patient 50,similar to the operation of robot base 10 and powered wheels 12. Thisstabilization may prevent camera tracking system 6 from moving during amedical procedure and may keep camera 46 from losing track of one ormore DRAs 52 connected to an anatomical structure 54 and/or tool 58within a designated area 56 as shown in FIGS. 3 and 5. This stabilityand maintenance of tracking enhances the ability of surgical robot 4 tooperate effectively with camera tracking system 6. Additionally, thewide camera base 38 may provide additional support to camera trackingsystem 6. Specifically, a wide camera base 38 may prevent cameratracking system 6 from tipping over when camera 46 is disposed over apatient, as illustrated in FIGS. 3 and 5. Without the wide camera base38, the outstretched camera 46 may unbalance camera tracking system 6,which may result in camera tracking system 6 falling over.

Camera telescoping support 40 may support camera 46. In someembodiments, telescoping support 40 moves camera 46 higher or lower inthe vertical direction. Telescoping support 40 may be made of anysuitable material in which to support camera 46. Suitable material maybe, but is not limited to, metal such as titanium, aluminum, orstainless steel, carbon fiber, fiberglass, or heavy-duty plastic. Camerahandle 48 may be attached to camera telescoping support 40 at anysuitable location. Cameral handle 48 may be any suitable handleconfiguration. A suitable configuration may be, but is not limited to, abar, circular, triangular, square, and/or any combination thereof. Asillustrated in FIG. 1, camera handle 48 may be triangular, allowing anoperator to move camera tracking system 6 into a planned position beforea medical operation. In some embodiments, camera handle 48 is used tolower and raise camera telescoping support 40. Camera handle 48 mayperform the raising and lowering of camera telescoping support 40through the depression of a button, switch, lever, and/or anycombination thereof.

Lower camera support arm 42 may attach to camera telescoping support 40at any suitable location, in embodiments, as illustrated in FIG. 1,lower camera support arm 42 may rotate three hundred and sixty degreesaround telescoping support 40. This free rotation may allow an operatorto position camera 46 in any suitable location. Lower camera support arm42 may be made of any suitable material in which to support camera 46.Suitable material may be, but is not limited to, metal such as titanium,aluminum, or stainless steel, carbon fiber, fiberglass, or heavy-dutyplastic. Cross-section of lower camera support arm 42 may be anysuitable shape. Suitable cross-sectional shape may be, but is notlimited to, circle, square, rectangle, hexagon, octagon, or i-beam. Thecross-sectional length and width may be about one to ten inches. Lengthof the lower camera support arm may be about four inches to aboutthirty-six inches. Lower camera support arm 42 may connect totelescoping support 40 by any suitable mechanism. Suitable mechanism maybe, but is not limited to, nuts and bolts, ball and socket fitting,press fitting, weld, adhesion, screws, rivets, clamps, latches, and/orany combination thereof. Lower camera support arm 42 may be used toprovide support for camera 46. Camera 46 may be attached to lower camerasupport arm 42 by any suitable mechanism. Suitable mechanism may be, butis not limited to, nuts and bolts, ball and socket fitting, pressfitting, weld, adhesion, screws, rivets, and/or any combination thereof.Camera 46 may pivot in any direction at the attachment area betweencamera 46 and lower camera support arm 42. In embodiments a curved rail44 may be disposed on lower camera support arm 42.

Curved rail 44 may be disposed at any suitable location on lower camerasupport arm 42. As illustrated in FIG. 3, curved rail 44 may attach tolower camera support arm 42 by any suitable mechanism. Suitablemechanism may be, but are not limited to nuts and bolts, ball and socketfitting, press fitting, weld, adhesion, screws, rivets, clamps, latches,and/or any combination thereof. Curved rail 44 may be of any suitableshape, a suitable shape may be a crescent, circular, oval, elliptical,and/or any combination thereof. In embodiments, curved rail 44 may beany appropriate length. An appropriate length may be about one foot toabout six feet. Camera 46 may be moveably disposed along curved rail 44.Camera 46 may attach to curved rail 44 by any suitable mechanism.Suitable mechanism may be, but are not limited to rollers, brackets,braces, motors, and/or any combination thereof. Motors and rollers, notillustrated, may be used to move camera 46 along curved rail 44. Asillustrated in FIG. 3, during a medical procedure, if an object preventscamera 46 from viewing one or more DRAs 52, the motors may move camera46 along curved rail 44 using rollers. This motorized movement may allowcamera 46 to move to a new position that is no longer obstructed by theobject without moving camera tracking system 6. While camera 46 isobstructed from viewing DRAs 52, camera tracking system 6 may send astop signal to surgical robot 4, display 34, and/or a tablet. The stopsignal may prevent SCARA 24 from moving until camera 46 has reacquiredDRAs 52. This stoppage may prevent SCARA 24 and/or end effector coupler22 from moving and/or using medical tools without being tracked bysurgical system 2.

End effector coupler 22, as illustrated in FIG. 6, is configured toconnect various types of passive end effectors to surgical robot 4 ofFIG. 2. End effector coupler 22 can include a saddle joint 62, anactivation assembly 60, a load cell 64 (FIG. 7), and a connector 66.Saddle joint 62 may attach end effector coupler 22 to SCARA 24. Saddlejoint 62 may be made of any suitable material. Suitable material may be,but is not limited to metal such as titanium, aluminum, or stainlesssteel, carbon fiber, fiberglass, or heavy-duty plastic. Saddle joint 62may be made of a single piece of metal which may provide end effectorwith additional strength and durability. The saddle joint 62 may attachto SCARA 24 by an attachment point 68. There may be a plurality ofattachment points 68 disposed about saddle joint 62. Attachment points68 may be sunk, flush, and/or disposed upon saddle joint 62. In someexamples, screws, nuts and bolts, and/or any combination thereof maypass through attachment point 68 and secure saddle joint 62 to SCARA 24.The nuts and bolts may connect saddle joint 62 to a motor, notillustrated, within SCARA 24. The motor may move saddle joint 62 in anydirection. The motor may further prevent saddle joint 62 from movingfrom accidental bumps and/or accidental touches by actively serving atthe current location or passively by applying spring actuated brakes.

The end effector coupler 22 can include a load cell 64 interposedbetween the saddle join 62 and a connected passive end effector. Loadcell 64, as illustrated in FIG. 7 may attach to saddle joint 62 by anysuitable mechanism. Suitable mechanism may be, but is not limited to,screws, nuts and bolts, threading, press fitting, and/or any combinationthereof.

FIG. 8 illustrates a block diagram of components of a surgical system800 according to some embodiments of the present disclosure. Referringto FIGS. 7 and 8, load cell 64 may be any suitable instrument used todetect and measure forces. In some examples, load cell 64 may be a sixaxis load cell, a three-axis load cell or a uniaxial load cell. Loadcell 64 may be used to track the force applied to end effector coupler22. In some embodiments the load cell 64 may communicate with aplurality of motors 850, 851, 852, 853, and/or 854. As load cell 64senses force, information as to the amount of force applied may bedistributed from a switch array and/or a plurality of switch arrays to acontroller 846. Controller 846 may take the force information from loadcell 64 and process it with a switch algorithm. The switch algorithm isused by the controller 846 to control a motor driver 842. The motordriver 842 controls operation of one or more of the motors. Motor driver842 may direct a specific motor to produce, for example, an equal amountof force measured by load cell 64 through the motor. In someembodiments, the force produced may come from a plurality of motors,e.g., 850-854, as directed by controller 846. Additionally, motor driver842 may receive input from controller 846. Controller 846 may receiveinformation from load cell 64 as to the direction of force sensed byload cell 64. Controller 846 may process this information using a motioncontroller algorithm. The algorithm may be used to provide informationto specific motor drivers 842. To replicate the direction of force,controller 846 may activate and/or deactivate certain motor drivers 842.Controller 846 may control one or more motors, e.g. one or more of850-854, to induce motion of passive end effector 1100 in the directionof force sensed by load cell 64. This force-controlled motion may allowan operator to move SCARA 24 and passive end effector 1100 effortlesslyand/or with very little resistance. Movement of passive end effector1100 can be performed to position passive end effector 1100 in anysuitable pose (i.e., location and angular orientation relative todefined three-dimensional (3D) orthogonal reference axes) for use bymedical personnel.

Connector 66 is configured to be connectable to the base of the passiveend effector 1100 and is connected to load cell 64. Connector 66 caninclude attachment points 68, a sensory button 70, tool guides 72,and/or tool connections 74. There may be a plurality of attachmentpoints 68 as shown in FIG. 6. Attachment points 68 may connect connector66 to load cell 64. Attachment points 68 may be sunk, flush, and/ordisposed upon connector 66. Attachment points 68 and 76 can be used toattach connector 66 to load cell 64 and/or to passive end effector 1100.In some examples, Attachment points 68 and 76 may include screws, nutsand bolts, press fittings, magnetic attachments, and/or any combinationthereof.

As illustrated in FIG. 6, a sensory button 70 may be disposed aboutcenter of connector 66. Sensory button 70 may be depressed when apassive end effector 1100 is connected to SCARA 24. Depression ofsensory button 70 may alert surgical robot 4, and in turn medicalpersonnel, that a passive end effector 1100 has been attached to SCARA24. As illustrated in FIG. 6, guides 72 may be used to facilitate properattachment of passive end effector 1100 to SCARA 24. Guides 72 may besunk, flush, and/or disposed upon connector 66. In some examples theremay be a plurality of guides 72 and may have any suitable patterns andmay be oriented in any suitable direction. Guides 72 may be any suitableshape to facilitate attachment of passive end effector 1100 to SCARA 24.A suitable shape may be, but is not limited to, circular, oval, square,polyhedral, and/or any combination thereof. Additionally, guides 72 maybe cut with a bevel, straight, and/or any combination thereof.

Connector 66 may have attachment points 74. As illustrated in FIG. 6,attachment points 74 may form a ledge and/or a plurality of ledges.Attachment points 74 may provide connector 66 a surface upon whichpassive end effector 1100 may clamp. In some embodiments, attachmentpoints 74 are disposed about any surface of connector 66 and oriented inany suitable manner in relation to connector 66.

Activation assembly 60, best illustrated in FIGS. 6 and 7, may encircleconnector 66. In some embodiments, activation assembly 60 may take theform of a bracelet that wraps around connector 66. In some embodiments,activation assembly 60, may be located in any suitable area withinsurgical system 2. In some examples, activation assembly 60 may belocated on any part of SCARA 24, any part of end effector coupler 22,may be worn by medical personnel (and communicate wirelessly), and/orany combination thereof. Activation assembly 60 may be made of anysuitable material. Suitable material may be, but is not limited toneoprene, plastic, rubber, gel, carbon fiber, fabric, and/or anycombination thereof. Activation assembly 60 may comprise of a primarybutton 78 and a secondary button 80. Primary button 78 and secondarybutton 80 may encircle the entirety of connector 66.

Primary button 78 may be a single ridge, as illustrated in FIG. 6, whichmay encircle connector 66. In some examples, primary button 78 may bedisposed upon activation assembly 60 along the end farthest away fromsaddle joint 62. Primary button 78 may be disposed upon primaryactivation switch 82, best illustrated on FIG. 7. Primary activationswitch 82 may be disposed between connector 66 and activation assembly60. In some examples, there may be a plurality of primary activationswitches 82, which may be disposed adjacent and beneath primary button78 along the entire length of primary button 78. Depressing primarybutton 78 upon primary activation switch 82 may allow an operator tomove SCARA 24 and end effector coupler 22. As discussed above, once setin place, SCARA 24 and end effector coupler 22 may not move until anoperator programs surgical robot 4 to move SCARA 24 and end effectorcoupler 22, or is moved using primary button 78 and primary activationswitch 82. In some examples, it may require the depression of at leasttwo non-adjacent primary activation switches 82 before SCARA 24 and endeffector coupler 22 will respond to operator commands. Depression of atleast two primary activation switches 82 may prevent the accidentalmovement of SCARA 24 and end effector coupler 22 during a medicalprocedure.

Activated by primary button 78 and primary activation switch 82, loadcell 64 may measure the force magnitude and/or direction exerted uponend effector coupler 22 by an operator, i.e. medical personnel. Thisinformation may be transferred to motors within SCARA 24 that may beused to move SCARA 24 and end effector coupler 22. Information as to themagnitude and direction of force measured by load cell 64 may cause themotors to move SCARA 24 and end effector coupler 22 in the samedirection as sensed by load cell 64. This force-controlled movement mayallow the operator to move SCARA 24 and end effector coupler 22 easilyand without large amounts of exertion due to the motors moving SCARA 24and end effector coupler 22 at the same time the operator is movingSCARA 24 and end effector coupler 22.

Secondary button 80, as illustrated in FIG. 6, may be disposed upon theend of activation assembly 60 closest to saddle joint 62. In someexamples secondary button 80 may comprise a plurality of ridges. Theplurality of ridges may be disposed adjacent to each other and mayencircle connector 66. Additionally, secondary button 80 may be disposedupon secondary activation switch 84. Secondary activation switch 84, asillustrated in FIG. 7, may be disposed between secondary button 80 andconnector 66. In some examples, secondary button 80 may be used by anoperator as a “selection” device. During a medical operation, surgicalrobot 4 may notify medical personnel to certain conditions by display 34and/or light indicator 28. Medical personnel may be prompted by surgicalrobot 4 to select a function, mode, and/or asses the condition ofsurgical system 2. Depressing secondary button 80 upon secondaryactivation switch 84 a single time may activate certain functions,modes, and/or acknowledge information communicated to medical personnelthrough display 34 and/or light indicator 28. Additionally, depressingsecondary button 80 upon secondary activation switch 84 multiple timesin rapid succession may activate additional functions, modes, and/orselect information communicated to medical personnel through display 34and/or light indicator 28. In some examples, at least two non-adjacentsecondary activation switches 84 may be depressed before secondarybutton 80 may function properly. This requirement may prevent unintendeduse of secondary button 80 from accidental bumping by medical personnelupon activation assembly 60. Primary button 78 and secondary button 80may use software architecture 86 to communicate commands of medicalpersonnel to surgical system 2.

FIG. 8 illustrates a block diagram of components of a surgical system800 configured according to some embodiments of the present disclosure,and which may correspond to the surgical system 2 above. Surgical system800 includes platform subsystem 802, computer subsystem 820, motioncontrol subsystem 840, and tracking subsystem 830. Platform subsystem802 includes battery 806, power distribution module 804, connector panel808, and charging station 810. Computer subsystem 820 includes computer822, display 824, and speaker 826. Motion control subsystem 840 includesdriver circuit 842, motors 850, 851, 852, 853, 854, stabilizers 855,856, 857, 858, end effector connector 844, and controller 846. Trackingsubsystem 830 includes position sensor 832 and camera converter 834.Surgical system 800 may also include a removable foot pedal 880 andremovable tablet computer 890.

Input power is supplied to surgical system 800 via a power source whichmay be provided to power distribution module 804. Power distributionmodule 804 receives input power and is configured to generate differentpower supply voltages that are provided to other modules, components,and subsystems of surgical system 800. Power distribution module 804 maybe configured to provide different voltage supplies to connector panel808, which may be provided to other components such as computer 822,display 824, speaker 826, driver 842 to, for example, power motors850-854 and end effector coupler 844, and provided to camera converter834 and other components for surgical system 800. Power distributionmodule 804 may also be connected to battery 806, which serves astemporary power source in the event that power distribution module 804does not receive power from an input power. At other times, powerdistribution module 804 may serve to charge battery 806.

Connector panel 808 may serve to connect different devices andcomponents to surgical system 800 and/or associated components andmodules. Connector panel 808 may contain one or more ports that receivelines or connections from different components. For example, connectorpanel 808 may have a ground terminal port that may ground surgicalsystem 800 to other equipment, a port to connect foot pedal 880, a portto connect to tracking subsystem 830, which may include position sensor832, camera converter 834, and marker tracking cameras 870. Connectorpanel 808 may also include other ports to allow USB, Ethernet, HDMIcommunications to other components, such as computer 822.

Control panel 816 may provide various buttons or indicators that controloperation of surgical system 800 and/or provide information fromsurgical system 800 for observation by an operator. For example, controlpanel 816 may include buttons to power on or off surgical system 800,lift or lower vertical column 16, and lift or lower stabilizers 855-858that may be designed to engage casters 12 to lock surgical system 800from physically moving. Other buttons may stop surgical system 800 inthe event of an emergency, which may remove all motor power and applymechanical brakes to stop all motion from occurring. Control panel 816may also have indicators notifying the operator of certain systemconditions such as a line power indicator or status of charge forbattery 806.

Computer 822 of computer subsystem 820 includes an operating system andsoftware to operate assigned functions of surgical system 800. Computer822 may receive and process information from other components (forexample, tracking subsystem 830, platform subsystem 802, and/or motioncontrol subsystem 840) in order to display information to the operator.Further, computer subsystem 820 may provide output through the speaker826 for the operator. The speaker may be part of the surgical robot,part of a head-mounted display component, or within another component ofthe surgical system 2. The display 824 may correspond to the display 34shown in FIGS. 1 and 2, or may be a head-mounted display which projectsimages onto a see-through display screen which forms an augmentedreality image that is overlaid on real-world objects viewable throughthe see-through display screen.

Tracking subsystem 830 may include position sensor 832 and cameraconverter 834. Tracking subsystem 830 may correspond to the cameratracking system 6 of FIG. 3. The marker tracking cameras 870 operatewith the position sensor 832 to determine the pose of DRAs 52. Thistracking may be conducted in a manner consistent with the presentdisclosure including the use of infrared or visible light technologythat tracks the location of active or passive elements of DRAs 52, suchas LEDs or reflective markers, respectively. The location, orientation,and position of structures having these types of markers, such as DRAs52, is provided to computer 822 and which may be shown to an operator ondisplay 824. For example, as shown in FIGS. 4 and 5, a surgical saw 1240having a DRA 52 or which is connected to an end effector coupler 22having a DRA 52 tracked in this manner (which may be referred to as anavigational space) may be shown to an operator in relation to a threedimensional image of a patient's anatomical structure.

Alternatively or additionally, the tracking subsystem 830 tracks a pose,e.g., rotational motion, of a surgical saw connected to the passive endeffector 1100 responsive to signaling from a light pulse detector andtracking ring that can be incorporated onto the passive end effector1100, such as described below for FIGS. 16 and 17.

Motion control subsystem 840 may be configured to physically movevertical column 16, upper arm 18, lower arm 20, or rotate end effectorcoupler 22. The physical movement may be conducted through the use ofone or more motors 850-854. For example, motor 850 may be configured tovertically lift or lower vertical column 16. Motor 851 may be configuredto laterally move upper arm 18 around a point of engagement withvertical column 16 as shown in FIG. 2. Motor 852 may be configured tolaterally move lower arm 20 around a point of engagement with upper arm18 as shown in FIG. 2. Motors 853 and 854 may be configured to move endeffector coupler 22 to provide translational movement and rotation alongin about three-dimensional axes. The surgical planning computer 910shown in FIG. 9 can provide control input to the controller 846 thatguides movement of the end effector coupler 22 to position a passive endeffector, which is connected thereto, with a planned pose (i.e.,location and angular orientation relative to defined 3D orthogonalreference axes) relative to an anatomical structure that is to be cutduring a surgical procedure. Motion control subsystem 840 may beconfigured to measure position of the passive end effector structureusing integrated position sensors (e.g. encoders). In one of theembodiments, position sensors are directly connected to at least onejoint of the passive end effector structure, but may also be positionedin another location in the structure and remotely measure the jointposition by interconnection of a timing belt, a wire, or any othersynchronous transmission interconnection.

FIG. 9 illustrates a block diagram of a surgical system computerplatform 900 that includes a surgical planning computer 910 which may beseparate from and operationally connected to a surgical robot 800 or atleast partially incorporated therein according to some embodiments ofthe present disclosure. Alternatively, at least a portion of operationsdisclosed herein for the surgical planning computer 910 may be performedby components of the surgical robot 800 such as by the computersubsystem 820.

Referring to FIG. 9, the surgical planning computer 910 includes adisplay 912, at least one processor circuit 914 (also referred to as aprocessor for brevity), at least one memory circuit 916 (also referredto as a memory for brevity) containing computer readable program code918, and at least one network interface 920 (also referred to as anetwork interface for brevity). The network interface 920 can beconfigured to connect to a C-Arm imaging device 104 in FIG. 10, an O-Armimaging device 106 in FIG. 11, another medical imaging device, an imagedatabase 950 of medical images, components of the surgical robot 800,and/or other electronic equipment.

When the surgical planning computer 910 is at least partially integratedwithin the surgical robot 800, the display 912 may correspond to thedisplay 34 of FIG. 2 and/or the tablet 890 of FIG. 8 and/or ahead-mounted display, the network interface 920 may correspond to theplatform network interface 812 of FIG. 8, and the processor 914 maycorrespond to the computer 822 of FIG. 8.

The processor 914 may include one or more data processing circuits, suchas a general purpose and/or special purpose processor, e.g.,microprocessor and/or digital signal processor. The processor 914 isconfigured to execute the computer readable program code 918 in thememory 916 to perform operations, which may include some or all of theoperations described herein as being performed by a surgical planningcomputer.

The processor 914 can operate to display on the display device 912 animage of a bone that is received from one of the imaging devices 104 and106 and/or from the image database 950 through the network interface920. The processor 914 receives an operator's definition of where ananatomical structure, i.e. one or more bones, shown in one or moreimages is to be cut, such as by an operator touch selecting locations onthe display 912 for planned surgical cuts or using a mouse-based cursorto define locations for planned surgical cuts.

The surgical planning computer 910 enables anatomy measurement, usefulfor knee surgery, like measurement of various angles determining centerof hip, center of angles, natural landmarks (e.g. transepicondylar line,Whitesides line, posterior condylar line), etc. Some measurements can beautomatic while some others be involve human input or assistance. Thissurgical planning computer 910 allows an operator to choose the correctimplant for a patient, including choice of size and alignment. Thesurgical planning computer 910 enables automatic or semi-automatic(involving human input) segmentation (image processing) for CT images orother medical images. The surgical plan for a patient may be stored in acloud-based server for retrieval by the surgical robot 800. During thesurgery, the surgeon will choose which cut to make (e.g. posteriorfemur, proximal tibia etc.) using a computer screen (e.g. touchscreen)or augmented reality interaction via, e.g., a head-mounted display. Thesurgical robot 4 may automatically move the surgical saw to a plannedposition so that a target plane of planned cut is optimally placedwithin a workspace of the passive end effector interconnecting thesurgical saw and the robot arm 20.

In some embodiments, the surgical system computer platform 900 can usetwo DRAs to tracking patient anatomy position: one on patient tibia andone on patient femur. The platform 900 may use standard navigatedinstruments for the registration and checks (e.g. a pointer similar tothe one used in Globus ExcelsiusGPS system for spine surgery). Trackingmarkers allowing for detection of DRAs movement in reference to trackedanatomy can be used as well.

A particularly challenging task in knee surgery is how to plan theposition of the implant in the knee and many surgeons struggle with thistask on a computer screen which is a 2D representation of 3D anatomy.The platform 900 could address this problem by using a augmented reality(AR) head-mounted display to generate an implant overlay around theactual patient knee. For example, the surgeon can be operationallydisplayed a virtual handle to grab and move the implant to a desiredpose and adjust planned implant placement. Afterward, during surgery,the platform 900 could render the navigation through the AR head-mounteddisplay to show surgeon what is not directly visible. Also, the progressof bone removal, e.g., depth or cut, can be displayed in real-time.Other features that may be displayed through AR can include, withoutlimitation, gap or ligament balance along a range of joint motion,contact line on the implant along the range of joint motion, ligamenttension and/or laxity through color or other graphical renderings, etc.

The surgical planning computer 910, in some embodiments, can allowplanning for use of standard implants, e.g., posterior stabilizedimplants and cruciate retaining implants, cemented and cementlessimplants, revision systems for surgeries related to, for example, totalor partial knee and/or hip replacement and/or trauma.

The processor 912 may graphically illustrate on the display 912 one ormore cutting planes intersecting the displayed anatomical structure atthe locations selected by the operator for cutting the anatomicalstructure. The processor 912 also determines one or more sets of angularorientations and locations where the end effector coupler 22 should bepositioned so a cutting plane of the surgical saw will be aligned with atarget plane to perform the operator defined cuts, and stores the setsof angular orientations and locations as data in a surgical plan datastructure. The processor 912 uses the known range of movement of thetool attachment mechanism of the passive end effector to determine wherethe end effector coupler 22 attached to the robot arm 20 needs to bepositioned.

The computer subsystem 820 of the surgical robot 800 receives data fromthe surgical plan data structure and receives information from thecamera tracking system 6 indicating a present pose of an anatomicalstructure that is to be cut and indicating a present pose of the passiveend effector and/or surgical saw tracked through DRAs. The computersubsystem 820 determines a pose of the target plane based on thesurgical plan defining where the anatomical structure is to be cut andbased on the pose of the anatomical structure. The computer subsystem820 generates steering information based on comparison of the pose ofthe target plane and the pose of the surgical saw. The steeringinformation indicates where the passive end effector needs to be movedso the cutting plane of the saw blade becomes aligned with the targetplane and the saw blade becomes positioned a distance from theanatomical structure to be cut that is within the range of movement ofthe tool attachment mechanism of the passive end effector.

As explained above, a surgical robot includes a robot base, a robot armrotatably connected to the robot base, and at least one motoroperatively connected to move the robot arm relative to the robot base.The surgical robot also includes at least one controller, e.g. thecomputer subsystem 820 and the motion control subsystem 840, connectedto the at least one motor and configured to perform operations.

As will be explained in further detail below with regard to FIGS. 12-17,passive end effectors are disclosed that interconnect a surgical saw tothe end effector coupler of the robot arm of a surgical robot. Thepassive end effectors include a rotational disk rotatably connected abase which is connected to the end effector coupler, and includes a sawattachment that us rotatably connected to the rotational disk. The sawattachment is configured to connect to a surgical saw having a saw bladeconfigured to oscillate for cutting. The saw attachment rotates aboutthe rotational disk and the rotational disk rotates about the base armto constrain cutting of the saw blade to a range of movement alongarcuate paths within a cutting plane.

In one embodiment, the controller(s) of the surgical robot controlsmovement of the at least one motor based on the steering information toreposition the passive end effector so the cutting plane of the sawblade becomes aligned with the target plane and the saw blade becomespositioned a distance from the anatomical structure to be cut that iswithin the range of movement of the saw blade provided by the rotationaldisk.

In another embodiment, the controller(s) of the surgical robot providethe steering information to a display device for display to guideoperator movement of the passive end effector so the cutting plane ofthe saw blade becomes aligned with the target plane and so the saw bladebecomes positioned the distance from the anatomical structure, which isto be cut, that is within the range of movement of the passive endeffector. The display device may correspond to the display 824 (FIG. 8),the display 34 of FIG. 1, and/or a head-mounted display.

For example, the steering information may be displayed on a head-mounteddisplay which projects images onto a see-through display screen whichforms an augmented reality image that is overlaid on real-world objectsviewable through the see-through display screen. The controller(s) ofthe surgical robot may display a graphical representation of the targetplane with a pose overlaid on a bone and with a relative orientationthere between corresponding to the surgical plan for how the bone isplanned to be cut. Alternatively or additionally, a graphicalrepresentation of the cutting plane of the saw blade can be displayed sothat an operator may more easily align the cutting plane with theplanned target plane for cutting the bone. The operator may therebyvisually observe and perform movements to align the cutting plane of thesaw blade with the target plane so the saw blade becomes positioned atthe planned pose relative to the bone and within a range of movement ofthe tool attachment mechanism of the passive end effector.

An automated imaging system can be used in conjunction with the surgicalplanning computer 910 and/or the surgical system 2 to acquirepre-operative, intra-operative, post-operative, and/or real-time imagedata of a patient. Example automated imaging systems are illustrated inFIGS. 10 and 11. In some embodiments, the automated imaging system is aC-arm 104 (FIG. 10) imaging device or an O-arm® 106 (FIG. 11). (O-arm®is copyrighted by Medtronic Navigation, Inc. having a place of businessin Louisville, Colo., USA) It may be desirable to take x-rays of apatient from a number of different positions, without the need forfrequent manual repositioning of the patient which may be required in anx-ray system. C-arm 104 x-ray diagnostic equipment may solve theproblems of frequent manual repositioning and may be well known in themedical art of surgical and other interventional procedures. Asillustrated in FIG. 10, a C-arm includes an elongated C-shaped memberterminating in opposing distal ends 112 of the “C” shape. C-shapedmember is attached to an x-ray source 114 and an image receptor 116. Thespace within C-arm 104 of the arm provides room for the physician toattend to the patient substantially free of interference from the x-raysupport structure.

The C-arm is mounted to enable rotational movement of the arm in twodegrees of freedom, (i.e. about two perpendicular axes in a sphericalmotion). C-arm is slidably mounted to an x-ray support structure, whichallows orbiting rotational movement of the C-arm about its center ofcurvature, which may permit selective orientation of x-ray source 114and image receptor 116 vertically and/or horizontally. The C-arm mayalso be laterally rotatable, (i.e. in a perpendicular direction relativeto the orbiting direction to enable selectively adjustable positioningof x-ray source 114 and image receptor 116 relative to both the widthand length of the patient). Spherically rotational aspects of the C-armapparatus allow physicians to take x-rays of the patient at an optimalangle as determined with respect to the particular anatomical conditionbeing imaged.

The O-arm® 106 illustrated in FIG. 11 includes a gantry housing 124which may enclose an image capturing portion, not illustrated. The imagecapturing portion includes an x-ray source and/or emission portion andan x-ray receiving and/or image receiving portion, which may be disposedabout one hundred and eighty degrees from each other and mounted on arotor (not illustrated) relative to a track of the image capturingportion. The image capturing portion may be operable to rotate threehundred and sixty degrees during image acquisition. The image capturingportion may rotate around a central point and/or axis, allowing imagedata of the patient to be acquired from multiple directions or inmultiple planes.

The O-arm® 106 with the gantry housing 124 has a central opening forpositioning around an object to be imaged, a source of radiation that isrotatable around the interior of gantry housing 124, which may beadapted to project radiation from a plurality of different projectionangles. A detector system is adapted to detect the radiation at eachprojection angle to acquire object images from multiple projectionplanes in a quasi-simultaneous manner. The gantry may be attached to asupport structure O-arm® support structure, such as a wheeled mobilecart with wheels, in a cantilevered fashion. A positioning unittranslates and/or tilts the gantry to a planned position andorientation, preferably under control of a computerized motion controlsystem. The gantry may include a source and detector disposed oppositeone another on the gantry. The source and detector may be secured to amotorized rotor, which may rotate the source and detector around theinterior of the gantry in coordination with one another. The source maybe pulsed at multiple positions and orientations over a partial and/orfull three hundred and sixty degree rotation for multi-planar imaging ofa targeted object located inside the gantry. The gantry may furthercomprise a rail and bearing system for guiding the rotor as it rotates,which may carry the source and detector. Both and/or either O-arm® 106and C-arm 104 may be used as automated imaging system to scan a patientand send information to the surgical system 2.

Images captured by the automated imaging system can be displayed adisplay device of the surgical planning computer 910, the surgical robot800, and/or another component of the surgical system 2.

Various embodiments of passive end effectors that are configured for usewith a surgical system are now described in the context of FIGS. 12-17.

FIG. 12 illustrates an exploded view of components of a passive endeffector 1100 that can be connected to a surgical saw 1240 and which areconfigured in accordance with some embodiments of the presentdisclosure. FIG. 13 illustrates the assembled passive end effector ofFIG. 12 connected to the surgical saw 1240 and configured in accordancewith some embodiments of the present disclosure.

Referring to FIGS. 12 and 13, the passive end effector 1100 includes abase 1200, a rotational disk 1210, and a saw attachment 1220. The base1200 is configured to attach to an end effector coupler 22 of the robotarm that is positioned by a surgical robot. Various attachmentmechanisms may be used to firmly attach the base 1200 to the endeffector coupler 22, removing backlash and ensuring suitable stiffness.Clamping mechanisms which may be used to attach the base 1200 to the endeffector coupler 22 can include but are not limited to toggle jointmechanisms or locking screw(s). The base 1200 includes a base arm 1201that extends away from the end effector coupler 22. The rotational disk1210 is rotatably connected to the base arm and rotates about a firstlocation 1212 on the rotational disk relative to a location 1202 on thebase arm 1201. The rotational disk 1210 may be connected to the base arm1201 by, for example, a bolt extending through locations 1212 and 1202of the rotational disk 1210 and base arm 1201, respectively. Therotational disk 1210 may alternatively or additionally connect to thebase arm 1201 through various mechanisms that can include, but are notlimited to, a screw, clamp, latch, tie, or press fit.

The saw attachment 1220 is rotatably connected to the rotational disk1210 and rotates about a second location 1214 on the rotational disk1210. The first location 1212 on the rotational disk 1210 is spacedapart from the second location 1214 on the rotational disk 1210. The sawattachment 1220 is configured to connect to the surgical saw 1240 havinga saw blade 1242 configured to oscillate for cutting. An exampleembodiment of the saw attachment 1222 is illustrated in FIG. 12 ashaving a cylindrical-shaped channel 1222 adapted to receive and retain acorresponding cylindrical-shaped portion of a housing of the surgicalsaw 1240. The saw attachment 1222 may alternatively or additionallyconnect to the surgical saw 1240 through various mechanisms that caninclude, but are not limited to, a screw, nut and bolt, clamp, latch,tie, press fit, or magnet. The saw attachment 1240 rotates about therotational disk 1210 and the rotational disk 1210 rotates about the basearm 1201 to constrain cutting of the saw blade 1242 to a range ofmovement along arcuate paths within a cutting plane.

For example, FIG. 13 illustrates three sequentially generated arcuatepaths made by a surgeon with the end of the saw blade 1242 by moving thesurgical saw 1240 while connected to the saw attachment 1220. Thesurgical saw 1240 is rotated relative to rotational disk 1210 about axis1214 to make an arcuate cut along path 1306 by the end of the saw blade1242 into an anatomical structure. The surgical saw 1240 is then thrustforward toward the anatomical structure through rotation of therotational disk 1210 relative to the base arm 1201 about axis 1202. Thesurgical saw 1240 is again rotated relative to rotational disk 1210about axis 1214 to provide another arcuate cut by the end of the sawblade 1242 deeper into the anatomical structure along path 1304. Thesurgical saw 1240 is then thrust further forward toward the anatomicalstructure through rotation of the rotational disk 1210 relative to thebase arm 1201 about axis 1202. The surgical saw 1240 is again rotatedrelative to rotational disk 1210 about axis 1214 to provide anotherarcuate cut deeper into the anatomical structure along path 1302. Asurgeon can more continuously thrust and rotate the surgical saw 1240 toperform cutting of the anatomical structure with arcuate movements ofthe saw blade.

The distance 1300 between the location 1214, where the saw attachment1220 connects to the rotational disk 1210, and the location 1202, wherethe rotational disk 1210 connects to the base arm 1201, constrains therange of thrusting motion of the end of the saw blade 1242 and,correspondingly, controls the depth of cut that can be made by thesurgical saw 1240 into an anatomical structure while the surgical robotmaintains, e.g., locks, the robot arm 20 (FIG. 2) and end effectorcoupler 22 with a fixed pose relative to the anatomical structure. Forexample, as shown in FIG. 13, the depth of cut 1310 made by the end ofthe saw blade 1242 is constrained by the extent of rotational movementof the rotational disk 1210 relative to the base arm 1200 that occurswhen thrusting toward the anatomical structure. At least someembodiments, the depth of cut is constrained to be not greater than thedistance 1300 between the connection locations 1214 and 1202.

FIGS. 14a-14d illustrate a sequence of top views of the passive endeffector 1100 and surgical saw 1240 of FIG. 13 in which the surgical saw1240 is rotated about the rotational disk 1210 and the rotational disk1210 is sequentially rotated clockwise rotated about the base arm 1201to provide a range of movement of the saw blade along arcuate pathswithin a cutting plane in accordance with some embodiments of thepresent disclosure. The sequence of top views illustrates four differentorientations of the location 1214, where the saw attachment 1220 fixedto the surgical saw 1240 connects to the rotational disk 1210, relativeto the location 1210, where the rotational disk 1210 connects to thebase arm 1201. The distance that the tip of the saw 1240 can be thrustto the right of the base arm 1201 decreases from when the location 1214is to the right of location 1202, as shown in FIGS. 14a and 14b ,relative to when the location 1214 is to the left of location 1202, asshown in FIGS. 14c and 14 d.

During a non-limiting example surgical procedure, a surgeon mayrepetitively rotate the saw blade back and forth while slowly rotatingthe rotational disk 1210 clockwise from the orientation illustrated inFIG. 14c to the orientation illustrated in FIG. 14d , which thrusts theend of the surgical saw along an arcuate cutting path into an anatomicalstructure located to the right of the base arm 1201. The surgeon maythen cut deeper into the anatomical structure by continuing to rotatethe rotational disk 1210 in a clockwise direction from the orientationillustrated in FIG. 14a to the orientation illustrated in FIG. 14b whilerepetitively rotating the saw blade back and forth, which furtherthrusts the end of the surgical saw along an arcuate cutting path intothe anatomical structure.

FIG. 15 illustrates a combination of the top views of the passive endeffector and surgical saw of FIGS. 14a and 14c to show ranges of themovement of the saw blade along a horizontal axis that are provided byrotation of the surgical saw 1240 about the rotational disk 1210 androtation of the rotational disk 1210 about the base arm 1201. In the topview configuration it is observed that while the location 1214 ismaintained at a fixed angle to the right of location 1202, the tip ofthe saw blade can be rotated along cutting circle 1502. In the bottomview configuration the rotational disk 1210 has been rotated 180° withthe location 1214 now maintained at another fixed angle to the left oflocation 1202, which results in the tip of the saw blade being rotatablealong another cutting circle 1504. The cutting circle 1502 of the topview configuration extends further to the right than the cutting circle1504 of the bottom view configuration, which corresponds to a differencein cutting depth 1500 between the top and bottom view configurations. Asexplained above, the distance between the locations 1202 and 1214controls the cutting depth 1500. Increasing the distance betweenlocations 1202 and 1214 increases the cutting depth 1500, and incontrast decreasing the distance between locations 1202 and 1214decreases the cutting depth 1500.

In some embodiments, the distance that the location 1202 on therotational disk 1210, where the rotational disk 1210 connects to thebase arm 1201, is spaced apart from the location 1214 on the rotationaldisk 1210, where the saw attachment 1220 connects to the rotational disk1210, is less than the first radius. For many orthopedic surgeries, ithas been determined that a distance that the location 1202 on therotational disk 1210 is spaced apart from the location 1214 on therotational disk 1202 should preferably be within a range of at least 1inch to not greater than 2.5 inches so the saw blade can be moved from astarting location where the surgical robot helped position the passiveend effector 1100 relative to an anatomical structure to be cut, througha range of thrusting distances that constrain the depth of cutting ofthe anatomical structure to avoid excessive cutting beyond theanatomical structure, e.g., femur. It has further been determined thatfor some types of orthopedic surgeries, such as knee surgeries, thedistance that the location 1202 on the rotational disk 1210 is spacedapart from the location 1214 on the rotational disk 1210 shouldpreferably be within a range of at least 1.5 inch to not greater than 2inches.

In some embodiments, the rotational disk has a recessed sector portionthat facilitates maintaining a desired minimum distance from theanatomical structure being cut while the rotational disk is beinginitially positioned and then rotated during surgery. In the exampleshown in FIG. 14a , the rotational disk 1210 includes a first sectorportion and a second sector portion, where the first sector portion hasa first radius between the location 1202 and an edge surface 1400 of thefirst section portion, and where the second sector portion has a secondradius between the location 1202 and an edge surface 1402 of the secondsector portion. The second radius is larger than the first radius. Thesaw attachment is rotatably connected to the second portion of therotational disk with the location 1214, where the saw attachment 1220connects to the rotational disk 10, being closer to the edge surface1402 of the second portion than to the edge surface 1400 of the firstportion.

During surgery, the surgical robot 4 can be configured to move the endeffector coupler 22, and the passive end effector and attached surgicalsaw, automatically to a position close to a knee or other anatomicalstructure, so that all bone to be cut is within the workspace of thepassive end effector. This position depends on the cut to be made andthe surgery planning and implant construction.

When the surgical robot 4 achieves a planned position, it holds theposition (either on brakes or active motor control) and does not moveduring the particular bone cut. It is the passive end effector thatallows movement of the saw blade of the surgical saw along the plannedtarget plane. Such planar cuts are particularly useful for classicaltotal knee arthroplasty where all bone cuts are planar. In partial kneearthroplasty there are special types of implants, called “on-lay” whichcan be in conjunction with saw-prepared bone surfaces. The variouspassive end effectors have mechanical structure that can ensureprecision of guidance during cuts, with higher precision than classicaljigs, and provide sufficient range of workspace range to cut all thebone that is planned and while provide sufficient transverse stiffness(corresponding to locked DOF) despite possibly significant amount ofvibrations originating from the surgical saw in addition to forcesapplied by the surgeon and bone reactionary forces.

It is preferable to measure the passive end effector position because itenables the surgical robot 4 to inform the surgeon how much bone hasbeen removed (procedure advancement). One way to provide real-timeinformation on bone removal is for the surgical robot 4 to measure wherethe saw blade passed in reference to the bone because the blade can passonly where the bone has been cut.

In one embodiment, a conventional sagittal saw mechanism can be usedwith the surgical system computer platform 900 with little or nochanges. The potential changes would involve adapting an external shieldto enable easy attachment of the surgical saw to the passive endeffector but would not necessarily involve changes in the internalmechanics. The passive end effector may be configured to connect to aconventional sagittal saw provided by, for example, DeSoutter company.

To prevent the saw from unintentional passive end effector movement whenthe surgical robot 4 positions the passive end effector, e.g., toprevent the surgical saw from falling on the patient due togravitational forces, the passive end effector can include a lockmechanism that moves between engaged and disengaged operations. Whileengaged, the lock mechanism prevents movement of the saw blade withrespect to the robot end effector coupler, either directly by lockingthe degree of freedoms (DOFs) of the surgical saw, or indirectly bybraking or locking specifics joints of the passive end effector. Whiledisengaged, the first and second planar mechanisms of the passive endeffector can be moved relative to the base without interference from thelock mechanism. The lock mechanism may also be used when a surgeon holdsthe surgical saw and controls the surgical robot 4 movement by applyingforces and torques to the surgical saw. The surgical robot 4, using theload cell 64 of FIGS. 6 and 7 integrated in the distal end of the robotarm 22, measures forces and torques that are applied and generatesresponsive forces and torques on the robot arm 22 so the surgeon canmore easily move the passive end effector back and forth, left andright, apply rotations around various axes.

As explained above, a surgical system (e.g., surgical system 2 in FIGS.1 and 2) includes the surgical robot (e.g., surgical robot 4 in FIGS. 1and 2) and the tracking system (e.g., camera tracking system 6 in FIGS.1 and 3).

The tracking system can be configured to determine a pose of ananatomical structure that is to be cut and to determine a pose of a sawblade of a surgical saw connected to a passive end effector supported bythe robot arm. The tracking system may determine the range of movementof the saw blade along arcuate paths within the cutting plane whileconnected to the passive end effector.

The surgical robot includes the robot base and the robot arm that isrotatably connected to the robot base and configured to position thepassive end effector. At least one motor is operatively connected tomove the robot arm relative to the robot base. At least one controlleris connected to control movement of the at least one motor. Thecontroller(s) of the surgical robot is configured to determine a pose ofa target plane based on a surgical plan defining where the anatomicalstructure is to be cut and based on the pose of the anatomicalstructure. The controller(s) is further configured to generate steeringinformation based on comparison of the pose of the target plane and thedetermined range of movement of the saw blade along arcuate paths withinthe cutting plane. The steering information indicates where the passiveend effector needs to be moved to position the cutting plane of the sawblade to be aligned with the target plane and so the saw blade is withinthe range of movement from the anatomical structure to be cut.

In some further embodiments, the controller(s) of the surgical robotcontrols movement of the motor(s) based on the steering information toreposition the passive end effector so the cutting plane of the sawblade becomes aligned with the target plane and the saw blade becomespositioned a distance from the anatomical structure to be cut that iswithin the range of movement of the saw blade provided by the rotationaldisk.

In some alternative or further embodiments, the controller(s) of thesurgical robot provides the steering information to a display device fordisplay to guide operator movement of the passive end effector so thecutting plane of the saw blade becomes aligned with the target plane andso the saw blade becomes positioned a distance from the anatomicalstructure to be cut that is within the range of movement of the sawblade provided by rotation of the rotational disk.

As explained above, some surgical systems can include head-mounteddisplay devices that can be worn by a surgeon, nurse practitioner,and/or other persons assisting with the surgical procedure. A surgicalsystem can display information that allows the wearer to position thepassive end effector more accurately and/or to confirm that it has beenpositioned accurately with the saw blade aligned with the target planefor cutting a planned location on an anatomical structure. The operationto provide the steering information to the display device, may includegenerating the steering information for display on a head-mounteddisplay device having a see-through display screen which displays thesteering information as an overlay on the anatomical structure to be cutto guide operator movement of the passive end effector so the cuttingplane of the saw blade becomes aligned with the target plane and the sawblade becomes positioned the distance from the anatomical structurewithin the range of movement of the saw blade provided by rotation ofthe rotational disk.

The operation to generate the steering information for display on thehead-mounted display device, may include generating a graphicalrepresentation of the target plane that is displayed as an overlayanchored to and aligned with the anatomical structure that is to be cut,and generating another graphical representation of the cutting plane ofthe saw blade that is displayed as an overlay anchored to and alignedwith the saw blade. A wearer may thereby move the surgical saw toprovide visually observed alignment between the graphically renderedtarget plane and the graphically rendered cutting plane.

The operation to generate the steering information for display on thehead-mounted display device, may include generating a graphicalrepresentation a depth of cut made by the saw blade into the anatomicalstructure being cut. Thus, the wearer can use the graphicalrepresentation of depth of cut to better monitor how the saw blade iscutting through bone despite direct observation of the cutting beingobstructed by tissue or other structure.

The tracking system can be configured to determine the pose of theanatomical structure that is to be cut by the saw blade based ondetermining a pose of tracking markers, e.g., DRAs, that are attached tothe anatomical structure, and can be configured to determine a pose ofthe surgical saw based on determining a pose of tracking markersconnected to at least one of the surgical saw and the passive endeffector. The tracking system can be configured to determine the pose ofthe surgical saw based on rotary position sensors which are configuredto measure rotational positions of the first and second planarmechanisms during movement of the tool attachment mechanism within theworking plane. As explained above, position sensors may be directlyconnected to at least one rotational connection, e.g., location 1202and/or location 1214) of the passive end effector structure, but mayalso be positioned in another location in the structure and remotelymeasure the joint position by interconnection of a measurement belt, awire, or any other synchronous transmission interconnection.

Another technical approach that can be used to facilitate tracking ofthe pose of surgical saw is to utilize a light source that shines lightonto a tracking ring which is on the rotational disk 1210, and a lightpulse detector that detects pulses of light that can be passed throughthe tracking ring or reflected therefrom. The tracking ring can beconfigured to generate pulses of light as the rotational disk is rotatedrelative to the light source. The tracking system can be configured todetermine the pose of the anatomical structure to be cut by the sawblade based on a determination of a pose of tracking markers that areattached to the anatomical structure, and configured to determine therange of movement of the saw blade along arcuate paths within thecutting plane while connected to the saw attachment based on countingpulses of light indicated by signaling received from the light pulsedetector.

FIG. 16 illustrates a light source 1610, a tracking ring 1600, and alight pulse detector 1620 that are configured in accordance with oneembodiment to provide input to the tracking system 830 for determiningan arcuate path through which the saw blade moves. The tracking ring1600 is also shown in FIG. 12. Referring to FIGS. 12 and 16, the lightsource 1610 can be connected to the base arm 1201 and oriented to emitlight toward the tracking ring 1600. The tracking ring 1600 is withinthe rotational disk 1210 and extends from a first side of the rotationaldisk 1210, which is adjacent to the base arm 1201, to a second side ofthe rotational disk 1210, which is adjacent to the saw attachment 1220.The tracking ring 1600 includes circumferentially spaced apartalternating areas of light translucent material and light opaquematerial. The light translucent material allows light from the lightsource 1610 to pass through from the first side to the second side. Incontrast, the light opaque material at least substantially preventslight from the light source 1610 from passing through from the firstside to the second side.

The light pulse detector 1620 is aligned to detect light pulses formedas light alternatively passes through the light translucent material ofthe tracking ring 1600 and as light is at least substantially preventedfrom passing through the light opaque material of the tracking ring 1600while the rotational disk 1210 is rotated relative to the base arm 1201.The light pulse detector 1620 may be connected to the rotational disk1210, the saw attachment 1220, or another structure of the surgicalrobot. The tracking system 830 is connected to receive signaling fromthe light pulse detector 1620, and is configured to determine an arcuatepath within the cutting plane through which the saw blade moves based onthe signaling from the light pulse detector 1620.

FIG. 17 illustrates a light source 1710, a tracking ring 1700, and alight pulse detector 1720 that are configured in accordance with anotherembodiment to provide input to the tracking system 830 for determiningan arcuate path through which the saw blade moves. Referring to FIG. 17,the light source 1710 can be connected to the base arm 1201 and orientedto emit light toward the tracking ring 1700. The tracking ring 1700 ison a side of the rotational disk 1210 adjacent to the base arm 1201, andincludes circumferentially spaced apart alternating areas of a firstmaterial that reflects incident light from the light source 1710 in adefined direction and a second material that at least substantiallyinhibits reflection of the incident light from the light source 1710 inthe defined direction. The light pulse detector 1720 can be connected tothe base arm 1201 and aligned to detect light pulses reflected in thefirst direction from the tracking ring 1700 while the rotational disk1210 is rotated relative to the base arm 1201. The tracking system 830is connected to receive signaling from the light pulse detector 1720,and is configured to determine an arcuate path within the cutting planethrough which the saw blade moves based on the signaling from the lightpulse detector 1720.

In some other embodiments, the tracking system 830 is configured todetermine the pose of the saw blade based on rotary position sensorsconnected to measure rotation of the rotational disk relative to thebase arm and/or to measure rotation of the saw attachment relative tothe rotational disk. Example types of rotary position sensors that canbe used with passive end effectors herein can include, but are notlimited to: potentiometer sensor; capacitive encoder; rotary variabledifferential transformer (RVDT) sensor; linear variable differentialtransformer (LVDT) sensor; Hall effect sensor; and incoder sensor.

FURTHER DEFINITIONS AND EMBODIMENTS

In the above-description of various embodiments of present inventiveconcepts, it is to be understood that the terminology used herein is forthe purpose of describing particular embodiments only and is notintended to be limiting of present inventive concepts. Unless otherwisedefined, all terms (including technical and scientific terms) usedherein have the same meaning as commonly understood by one of ordinaryskill in the art to which present inventive concepts belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of this specification andthe relevant art and will not be interpreted in an idealized or overlyformal sense expressly so defined herein.

When an element is referred to as being “connected”, “coupled”,“responsive”, or variants thereof to another element, it can be directlyconnected, coupled, or responsive to the other element or interveningelements may be present. In contrast, when an element is referred to asbeing “directly connected”, “directly coupled”, “directly responsive”,or variants thereof to another element, there are no interveningelements present. Like numbers refer to like elements throughout.Furthermore, “coupled”, “connected”, “responsive”, or variants thereofas used herein may include wirelessly coupled, connected, or responsive.As used herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. Well-known functions or constructions may not be described indetail for brevity and/or clarity. The term “and/or” includes any andall combinations of one or more of the associated listed items.

It will be understood that although the terms first, second, third, etc.may be used herein to describe various elements/operations, theseelements/operations should not be limited by these terms. These termsare only used to distinguish one element/operation from anotherelement/operation. Thus, a first element/operation in some embodimentscould be termed a second element/operation in other embodiments withoutdeparting from the teachings of present inventive concepts. The samereference numerals or the same reference designators denote the same orsimilar elements throughout the specification.

As used herein, the terms “comprise”, “comprising”, “comprises”,“include”, “including”, “includes”, “have”, “has”, “having”, or variantsthereof are open-ended, and include one or more stated features,integers, elements, steps, components or functions but does not precludethe presence or addition of one or more other features, integers,elements, steps, components, functions or groups thereof. Furthermore,as used herein, the common abbreviation “e.g.”, which derives from theLatin phrase “exempli gratia,” may be used to introduce or specify ageneral example or examples of a previously mentioned item, and is notintended to be limiting of such item. The common abbreviation “i.e.”,which derives from the Latin phrase “id est,” may be used to specify aparticular item from a more general recitation.

Example embodiments are described herein with reference to blockdiagrams and/or flowchart illustrations of computer-implemented methods,apparatus (systems and/or devices) and/or computer program products. Itis understood that a block of the block diagrams and/or flowchartillustrations, and combinations of blocks in the block diagrams and/orflowchart illustrations, can be implemented by computer programinstructions that are performed by one or more computer circuits. Thesecomputer program instructions may be provided to a processor circuit ofa general purpose computer circuit, special purpose computer circuit,and/or other programmable data processing circuit to produce a machine,such that the instructions, which execute via the processor of thecomputer and/or other programmable data processing apparatus, transformand control transistors, values stored in memory locations, and otherhardware components within such circuitry to implement thefunctions/acts specified in the block diagrams and/or flowchart block orblocks, and thereby create means (functionality) and/or structure forimplementing the functions/acts specified in the block diagrams and/orflowchart block(s).

These computer program instructions may also be stored in a tangiblecomputer-readable medium that can direct a computer or otherprogrammable data processing apparatus to function in a particularmanner, such that the instructions stored in the computer-readablemedium produce an article of manufacture including instructions whichimplement the functions/acts specified in the block diagrams and/orflowchart block or blocks. Accordingly, embodiments of present inventiveconcepts may be embodied in hardware and/or in software (includingfirmware, resident software, micro-code, etc.) that runs on a processorsuch as a digital signal processor, which may collectively be referredto as “circuitry,” “a module” or variants thereof.

It should also be noted that in some alternate implementations, thefunctions/acts noted in the blocks may occur out of the order noted inthe flowcharts. For example, two blocks shown in succession may in factbe executed substantially concurrently or the blocks may sometimes beexecuted in the reverse order, depending upon the functionality/actsinvolved. Moreover, the functionality of a given block of the flowchartsand/or block diagrams may be separated into multiple blocks and/or thefunctionality of two or more blocks of the flowcharts and/or blockdiagrams may be at least partially integrated. Finally, other blocks maybe added/inserted between the blocks that are illustrated, and/orblocks/operations may be omitted without departing from the scope ofinventive concepts. Moreover, although some of the diagrams includearrows on communication paths to show a primary direction ofcommunication, it is to be understood that communication may occur inthe opposite direction to the depicted arrows.

Many variations and modifications can be made to the embodiments withoutsubstantially departing from the principles of the present inventiveconcepts. All such variations and modifications are intended to beincluded herein within the scope of present inventive concepts.Accordingly, the above disclosed subject matter is to be consideredillustrative, and not restrictive, and the appended examples ofembodiments are intended to cover all such modifications, enhancements,and other embodiments, which fall within the spirit and scope of presentinventive concepts. Thus, to the maximum extent allowed by law, thescope of present inventive concepts are to be determined by the broadestpermissible interpretation of the present disclosure including thefollowing examples of embodiments and their equivalents, and shall notbe restricted or limited by the foregoing detailed description.

What is claimed is:
 1. A surgical system comprising: a passive end effector including a base configured to attach to an end effector coupler of a robot arm positioned by a surgical robot, the base including a base arm extending away from the end effector coupler, a rotational disk rotatably connected to the base arm, the rotational disk rotating about a first location on the rotational disk relative to the base arm, and a saw attachment rotatably connected to the rotational disk, the saw attachment rotating about a second location on the rotational disk, the first location on the rotational disk being spaced apart from the second location on the rotational disk, the saw attachment being configured to connect to a surgical saw having a saw blade configured to oscillate for cutting, the saw attachment rotating about the rotational disk and the rotational disk rotating about the base arm to constrain cutting of the saw blade to a range of movement along arcuate paths within a cutting plane.
 2. The surgical system of claim 1, further comprising: a tracking system configured to determine a pose of an anatomical structure to be cut by the saw blade and to determine the range of movement of the saw blade along arcuate paths within the cutting plane while connected to the saw attachment, wherein the surgical robot includes a robot base, the robot arm is rotatably connected to the robot base and configured to position the passive end effector, at least one motor operatively connected to move the robot arm relative to the robot base, and at least one controller connected to the at least one motor and configured to determine a pose of a target plane based on a surgical plan defining where the anatomical structure is to be cut and based on the pose of the anatomical structure, and generate steering information based on comparison of the pose of the target plane and the determined range of movement of the saw blade along arcuate paths within the cutting plane, the steering information indicating where the passive end effector needs to be moved to position the cutting plane of the saw blade to be aligned with the target plane and so the saw blade is within the range of movement from the anatomical structure to be cut.
 3. The surgical system of claim 2, the at least one controller being further configured to control movement of the at least one motor based on the steering information to reposition the passive end effector so the cutting plane of the saw blade becomes aligned with the target plane and the saw blade becomes positioned a distance from the anatomical structure to be cut that is within the range of movement of the saw blade provided by the rotational disk.
 4. The surgical system of claim 2, the at least one controller being further configured to provide the steering information to a display device for display to guide operator movement of the passive end effector so the cutting plane of the saw blade becomes aligned with the target plane and so the saw blade becomes positioned a distance from the anatomical structure to be cut that is within the range of movement of the saw blade provided by rotation of the rotational disk.
 5. The surgical system of claim 4, the at least one controller being further configured to generate the steering information for display on a head-mounted display device having a see-through display screen which displays the steering information as an overlay on the anatomical structure to be cut to guide operator movement of the passive end effector so the cutting plane of the saw blade becomes aligned with the target plane and the saw blade becomes positioned the distance from the anatomical structure within the range of movement of the saw blade provided by rotation of the rotational disk.
 6. The surgical system of claim 5, wherein when generating the steering information the at least one controller being further configured to generate a graphical representation of the target plane displayed as an overlay anchored to and aligned with the anatomical structure to be cut, and generate another graphical representation of the cutting plane of the saw blade displayed as an overlay anchored to and aligned with the saw blade.
 7. The surgical system of claim 5, wherein when generating the steering information the at least one controller being further configured to generate a graphical representation a depth of cut made by the saw blade into the anatomical structure being cut.
 8. The surgical system of claim 2, the tracking system being configured to determine the pose of the anatomical structure to be cut by the saw blade based on a determination of a pose of tracking markers that are attached to the anatomical structure, and being configured to determine a pose of the surgical saw based on a determination of a pose of tracking markers on at least one of the surgical saw and the passive end effector.
 9. The surgical system of claim 2, the tracking system being configured to determine the pose of the anatomical structure to be cut by the saw blade based on a determination of a pose of tracking markers that are attached to the anatomical structure, and being configured to determine the range of movement of the saw blade along arcuate paths within the cutting plane while connected to the saw attachment based on counting pulses of light indicated by signaling received from a light pulse detector that senses pulses of light from a tracking ring residing on the rotational disk, the tracking ring being configured to generate the pulses of light as the rotational disk is rotated relative to a light source residing on the base arm.
 10. The surgical system of claim 1, further comprising: a light source connected to the base arm and configured to emit light toward the rotational disk; a tracking ring within the rotational disk that extends from a first side of the rotational disk, which is adjacent to the base arm, to a second side of the rotational disk, which is adjacent to the saw attachment, the tracking ring including circumferentially spaced apart alternating areas of light translucent material and light opaque material, the light translucent material allowing light from the light source to pass through from the first side to the second side, the light opaque material at least substantially preventing light from the light source from passing through from the first side to the second side; a light pulse detector aligned to detect light pulses formed as light alternatively passes through the light translucent material of the tracking ring and as light is at least substantially prevented from passing through the light opaque material of the tracking ring while the rotational disk is rotated relative to the base arm; and a tracking system configured to determine an arcuate path within the cutting plane through which the saw blade moves based on signaling from the light pulse detector that is based detected light pulses.
 11. The surgical system of claim 1, further comprising: a light source connected to the base arm and configured to emit light toward the rotational disk; a tracking ring on a side of the rotational disk adjacent to the base arm, the tracking ring including circumferentially spaced apart alternating areas of a first material that reflects incident light from the light source in a defined direction and a second material that at least substantially inhibits reflection of the incident light from the light source in the defined direction; a light pulse detector connected to the base arm and aligned to detect light pulses reflected in the first direction from the tracking ring while the rotational disk is rotated relative to the base arm; and a tracking system configured to determine an arcuate path within the cutting plane through which the saw blade moves based on signaling from the light pulse detector that is based detected pulses of the light.
 12. The surgical system of claim 1, wherein: the rotational disk includes a first sector portion and a second sector portion, the first sector portion having a first radius between the first location and an edge surface of the first section portion, the second sector portion having a second radius between the first location and an edge surface of the second sector portion, the second radius being larger than the first radius; and the saw attachment is rotatably connected to the second portion of the rotational disk with the second location on the rotational disk being closer to the edge surface of the second portion than to the edge surface of the first portion.
 13. The surgical system of claim 12, wherein: a distance that the first location on the rotational disk is spaced apart from the second location on the rotational disk is less than the first radius.
 14. The surgical system of claim 1, wherein: a distance that the first location on the rotational disk is spaced apart from the second location on the rotational disk is within a range of at least 1 inch to not greater than 2.5 inches.
 15. The surgical system of claim 14, wherein: a distance that the first location on the rotational disk is spaced apart from the second location on the rotational disk is within a range of at least 1.5 inch to not greater than 2 inches.
 16. A surgical system comprising: a tracking system configured to determine a pose of an anatomical structure to be cut by a saw blade and to determine a range of movement of the saw blade along arcuate paths within a cutting plane; a surgical robot including a robot base, a robot arm rotatably connected to the robot base; at least one motor operatively connected to move the robot arm relative to the robot base, and at least one controller connected to the at least one motor and configured to perform operations; and a passive end effector including a base configured to attach to an end effector coupler of the robot arm, a rotational disk rotatably connected to the base arm, the rotational disk rotating about a first location on the rotational disk relative to the base arm, and a saw attachment rotatably connected to the rotational disk, the saw attachment rotating about a second location on the rotational disk, the first location on the rotational disk being spaced apart from the second location on the rotational disk, the saw attachment being configured to connect to a surgical saw having a saw blade configured to oscillate for cutting, the saw attachment rotating about the rotational disk and the rotational disk rotating about the base arm to constrain cutting of the saw blade to the range of movement along arcuate paths within the cutting plane, wherein the at least one controller is configured to determine a pose of a target plane based on a surgical plan defining where the anatomical structure is to be cut and based on the pose of the anatomical structure, and generate steering information based on comparison of the pose of the target plane and the determined range of movement of the saw blade along arcuate paths within the cutting plane, the steering information indicating where the passive end effector needs to be moved to position the cutting plane of the saw blade to be aligned with the target plane and so the saw blade is within the range of movement from the anatomical structure to be cut.
 17. The surgical system of claim 16, the at least one controller being further configured to control movement of the at least one motor based on the steering information to reposition the passive end effector so the cutting plane of the saw blade becomes aligned with the target plane and the saw blade becomes positioned a distance from the anatomical structure to be cut that is within the range of movement of the saw blade provided by rotation of the rotational disk.
 18. The surgical system of claim 16, the at least one controller being further configured to provide the steering information to a display device for display to guide operator movement of the passive end effector so the cutting plane of the saw blade becomes aligned with the target plane and so the saw blade becomes positioned a distance from the anatomical structure to be cut that is within the range of movement of the saw blade provided by rotation of the rotational disk.
 19. The surgical system of claim 16, the tracking system being configured to determine the pose of the anatomical structure to be cut by the saw blade based on a determination of a pose of tracking markers that are attached to the anatomical structure, and being configured to determine the range of movement of the saw blade along arcuate paths within the cutting plane while connected to the saw attachment based on counting pulses of light indicated by signaling from a light pulse detector that senses pulses of light from a tracking ring residing on the rotational disk, the tracking ring being configured to generate the pulses of light as the rotational disk is rotated relative to a light source residing on the base arm.
 20. The surgical system of claim 16, wherein: the rotational disk includes a first sector portion and a second sector portion, the first sector portion having a first radius between the first location and an edge surface of the first section portion, the second sector portion having a second radius between the first location and an edge surface of the second sector portion, the second radius being larger than the first radius; and the saw attachment is rotatably connected to the second portion of the rotational disk with the second location on the rotational disk being closer to the edge surface of the second portion than to the edge surface of the first portion.
 21. The surgical system of claim 20, wherein: a distance that the first location on the rotational disk is spaced apart from the second location on the rotational disk is less than the first radius.
 22. The surgical system of claim 16, wherein: a distance that the first location on the rotational disk is spaced apart from the second location on the rotational disk is within a range of at least 1 inch and not greater than 2.5 inches.
 23. The surgical system of claim 22, wherein: a distance that the first location on the rotational disk is spaced apart from the second location on the rotational disk is within a range of at least 1.5 inch and not greater than 2 inches.
 24. A robotic surgical system comprising: an end effector configured to attach to an end effector coupler of a robot arm positioned by a surgical robot, a rotational link rotatably connected to the end effector at a first rotation axis, and a saw attachment rotatably connected to the rotational link at a second rotation axis offset from the first rotation axis by a selected distance, the first and second rotation axes being parallel to each other, the saw attachment being configured to connect to a surgical saw for cutting, the saw attachment rotating about the second rotation axis and the rotational link rotating about the first axis to constrain cutting of the surgical saw to a range of movement along arcuate paths within a cutting plane. 